Processes for recovering valuable components from a catalytic fast pyrolysis process

ABSTRACT

Methods of separating products from the catalytic fast pyrolysis of biomass are described. In a preferred method, a portion of the products from a pyrolysis reactor are recovered and separated using a quench system and solvent contacting system that employs materials produced in the pyrolysis process.

RELATED APPLICATIONS

This application claims priority to U.S. Provisional Patent ApplicationNo. 62/019,881 filed Jul. 1, 2014.

INTRODUCTION

Since the beginning of the Industrial Age, human desires for travel andconsumer goods have driven the ever increasing consumption of fossilfuels such as coal and oil, typically obtained from deep underground.The extraction of fossil fuels by mining and drilling has often beenaccompanied by environmental and political costs. Furthermore, as themore accessible sources of fossil fuels are being used up; this has ledto the pursuit of more expensive extraction technologies such asfracking and deep sea drilling. Additionally, the consumption of fossilfuels causes higher levels of atmospheric carbon, typically in the formof carbon dioxide.

To reduce these problems, there have been extensive efforts made inconverting biomass to fuels and other useful chemicals. Unlike fossilfuels, biomass is renewable and carbon-neutral; that is, biomass-derivedfuels and chemicals do not lead to increased atmospheric carbon sincethe growth of biomass consumes atmospheric carbon. Much of the work onbiomass has involved converting refined biomass including vegetableoils, starches, and sugars; however, since these types of refinedbiomass may alternatively be consumed as food, there is even a greaterutility for converting non-food biomass such as agricultural waste(bagasse, straw, corn stover, corn husks, etc.), energy crops (likeswitch grass and saw grass), trees and forestry waste, such as woodchips and saw dust, waste from paper mills, plastic waste, recycledplastics or algae, in combination sometimes referred to as cellulosicbiomass. This non-food biomass generally includes three main components:lignin, hemicellulose, and cellulose.

Generating fuels and chemicals from biomass requires specializedconversion processes different from conventional petroleum-basedconversion processes due to the nature of the feedstock. Hightemperatures, solid feed, high concentrations of water, unusualseparations, and oxygenated by-products are some of the features ofbiomass conversion that are distinct from those encountered in petroleumupgrading. Thus, despite extensive efforts, there are many challengesthat must be overcome to efficiently produce chemicals from biomass.

It is well known that a variety of biomass-derived polymeric materialssuch as lignin, cellulose, and hemi-cellulose, can be pyrolyzed toproduce mixtures of aromatics, olefins, CO, CO2, water, and otherproducts. A particularly desirable form of pyrolysis is known ascatalytic fast pyrolysis (CFP) that involves the conversion of biomassin a catalytic fluid bed reactor to produce a mixture of aromatics,olefins, and a variety of other materials. The aromatics includebenzene, toluene, xylenes, (collectively BTX), and naphthalene, amongother aromatics. The olefins include ethylene, propylene, and lesseramounts of higher molecular weight olefins. BTX aromatics have highvalue and are easily transported.

The raw effluent from a CFP process is a complex mixture that comprisesaromatics, olefins, oxygenates, paraffins, H₂, CH₄, CO, CO₂, water,char, ash, coke, catalyst fines, and a host of other compounds.Separation and recovery of the various components from this complexmixture present challenges that, despite extensive and costly efforts,have not been solved satisfactorily.

Aromatics recovery from process streams has been an active area ofresearch and development for many years, but past processes have notbeen developed to effectively handle the complex mixture produced in theCFP process. For example, Arnold in U.S. Pat. No. 2,400,802 describes ascheme for separating aromatics from other hydrocarbons with an aqueoussolvent system at high pressure and temperatures, but does not addressthe presence of solids, oxygenates, or gases such as CO₂, CO, H₂, andlight hydrocarbons. Paret in U.S. Pat. No. 3,816,302 discloses a processfor solvent extraction of aromatics from mixtures using a solventcontaining morpholine, but does not address the presence of solids,oxygenates, water, or gases such as CO₂, CO, and H₂. Weith et al. inU.S. Pat. No. 3,996,129 describe a process for separating gases fromliquids in a process effluent comprising aromatics, but do not discussoxygenates or solids separation. In U.S. Pat. No. 4,086,159, Baxter andGurgiolo describe the extraction of aromatics from liquid mixturescontaining high concentrations of aromatics, olefins, and aliphatichydrocarbons using polyol solvents. They do not address solidsseparation or the handling of gases and oxygenates. Vidueira in U.S.Pat. No. 5,225,072 describes an extractive distillation with solventsthat have a polar function such as hydroxyl, amino, cyano, carboxyl ornitro group, wherein the aromatics are separated from the solvent in asteam stripping step; but no mention is made of separation of solids,fixed gases, or oxygenates. In U.S. Pat. No. 4,528,412, Steacy disclosesa process for dehydrocyclodimerization of C3-C4 paraffins to aromaticsand recovering aromatics using a lean absorption liquid stream but alsodo not discuss solids or oxygenates separation or recovery.

Patents for the quench and recovery of materials from hydrocarboncracking, such as U.S. Pat. No. 2,442,060 to Shepardson, describeprocesses for recovering and separating aromatics, but do not addressthe problems of catalyst, char, ash, coke, or oxygenates separation orrecovery. Likewise, steam cracking process patents, such as U.S. Pat.No. 3,923,921 to Kohfeldt, disclose the quenching of the raw effluentand separation and recovery of aromatics, but do not address theproblems of solids or oxygenates removal and recovery. In U.S. Pat. No.4,599,478, Kamisaka et al. describe a process for manufacturing olefinsby thermal cracking but without addressing the problem of oxygenates,catalyst, or other solids separation and recovery. Kurukchi, et al. inU.S. Pat. No. 6,576,132 disclose a process for treating quench waterfrom a stream cracker so the water can be recycled by stripping organiccompounds and filtering solids, but provide no information for oxygenateor catalyst separations and recovery. In U.S. Pat. No. 7,820,033, Eng,et al. describe a process for producing ethylene by cracking C4-C10hydrocarbons but do not mention of separating solids or recoveringoxygenates as products. U.S. Pat. No. 8,080,698 to Eng et al. similarlydescribes a dehydrogenation process for producing olefins but does notaddress catalyst, solids, char, ash, or oxygenate separation orrecovery. Further, Eng et al., in U.S. Published Patent Appl. No.2012/0165584, describes a system for producing olefins from hydrocarbonsby cracking, quenching, and catalytic upgrading, but does not separateor recover aromatics or oxygenates. Moore et al. in U.S. PublishedPatent Appl. No. 2013/0306557 describe a liquid-liquid extractionprocess using a low density, low water solubility solvent to concentratemany byproducts of the bio-oil obtained from a fast pyrolysis process.Platon et al. in U.S. Pat. No. 8,936,654 describe a process forquenching a highly reactive biomass pyrolysis product with a hydrocarbonsolvent that dilutes the pyrolysis oil to prevent the heaviest and mostreactive portions from polycondensation and thermal degradation. Theprocess is not applicable to catalytic pyrolysis products and water isnot considered a suitable quench liquid as it forms a separate phase anddoes not dilute the reactive components.

Thus, despite extensive efforts, a need remains for improved processesfor recovering and separating aromatic and oxygenate products producedfrom the product effluent of a catalytic pyrolysis process. The presentinvention provides recovery and separation processes that quenches thehot effluent, separates the complex product mixture, and recoversvaluable components.

SUMMARY OF THE INVENTION

In a first aspect, the invention provides a method for producingaromatic chemicals from the product stream of a catalytic pyrolysisprocess, comprising: quenching the product stream with water; separatinga first liquid product and a first vapor phase, recovering aromaticsfrom the first vapor phase; and recovering oxygenates from the firstliquid product. Preferably, the feed to the catalytic pyrolysis processcomprises biomass. In some preferred embodiments, the temperature of thefirst vapor phase is from 10° C. to 200° C., or from 20° C. to 150° C.,or from 30° C. to 100° C., or from 40° C. to 80° C., or from 50° C. to70° C. In some embodiments, the first vapor phase is condensed toproduce a second liquid phase and a second vapor phase from the firstvapor phase. The second liquid may comprise at least 50%, or at least65%, or at least 75%, or at least 85%, or from 65 to 99%, or from 75 to95%, or from 80 to 92%, or from 85 to 90% by weight benzene plus tolueneplus xylenes. In some embodiments, the second liquid phase comprisesless than 5%, or less than 2%, or less than 1%, or less than 0.25%, orfrom 0.01 to 5%, or from 0.03 to 2%, or from 0.05 to 1% by weightoxygenates. The invention also includes a liquid phase produced by theinventive methods. In some embodiments, an organic stream comprisingbenzene, toluene, xylenes, or ethyl benzene, or some combination ofthese is fed to the quench unit.

The invention may comprise: condensing the first vapor phase andseparating a second liquid phase and a second vapor phase; contactingthe first vapor phase or second vapor phase or a combination of themwith a contacting solvent to produce a third liquid phase and thirdvapor phase, and recovering aromatics from the second liquid phase andthe third liquid phase. In some preferred embodiments, the contactingsolvent comprises a liquid stream produced from biomass in the process;the contacting solvent may comprise a portion of the first liquidproduct or the second liquid phase (having the conventional meaning of aportion of the first liquid phaseor a portion of the second liquidphase). A portion of the xylenes-rich stream can be used as thecontacting solvent. In some preferred embodiment, the contacting solventcomprises (or consists essentially of) xylenes produced in the CFPprocess. Preferably, the first liquid product is separated into anorganic fraction and an aqueous fraction; the aqueous fraction maycomprise less than 10%, or less than 5%, or less than 3%, or less than2%, or from 0.1 to 10%, or from 0.5 to 5%, or from 1 to 3% aromatics byweight; the aqueous stream may comprise less than 10%, or less than 5%,or less than 2%, or less than 1%, or from 0.05 to 10%, or from 0.1 to5%, or from 0.5 to 3% oxygenates by weight; the organic stream maycomprises at least 80%, at least 85%, at least 90%, or at least 95%, orfrom 90 to 99.8% aromatics by weight; the organic stream may comprise atleast 40%, or at least 50%, or at least 60%, or from 40 to 90%, or from50 to 80%, or from 60 to 70% naphthalene by weight; the organic streammay comprise less than 25%, or less than 15%, or less than 10%, or from0.1 to 25%, or from 1 to 15%, or from 2 to 10% oxygenates by weight. Theinvention also includes any of the organic or aqueous liquid productstreams produced from the methods described herein. In some embodiments,an organic liquid product stream produced from the methods of theinvention may comprise at least 80% aromatics by mass, at least 40%polycyclic aromatics by mass, less than 25% monocyclic aromatics bymass, less than 25% oxygenates by mass, and less than 5% water by mass.In some embodiments, an organic liquid product stream produced from themethods of the invention may comprise from 60 to 99.8% aromatics bymass, from 40 to 90% polycyclic aromatics by mass, from 1 to 25% ofmonocyclic aromatics by mass, from 0.1 to 25% oxygenates by mass, andfrom 0.001 to 5% water by mass. Solids can be separated from the firstliquid product and/or the aqueous phase.

In some preferred methods, the first liquid product is separated into anorganic fraction and an aqueous fraction, and a portion of the organicphase is used as a contacting solvent.

Preferred contacting solvents may have a boiling point greater than theboiling point of toluene. In some embodiments, a first liquid product isseparated into an organic fraction and an aqueous fraction, and aportion of the aqueous fraction is used as quench water. Oxygenates maybe recovered from the organic fraction. In some embodiments, at least25%, or at least 50%, or at least 75%, or at least 90%, or at least 95%up to 100% of the water used in the quench liquid is water produced frombiomass in the process. All or a portion of the aqueous stream can becooled by heat exchange with a closed loop cooling water circuit; and/ormay be cooled in a fin-fan air cooled heat exchanger.

In some preferred embodiments, a fluidization gas of the CFP processcomprises a portion of the third vapor phase. A transport fluid used totransport biomass into the CFP reactor may comprise a portion of thethird vapor phase. In some preferred embodiments, the first vapor iscompressed before it is contacted with a contacting solvent.

In some particularly preferred embodiments, the raw CFP product streampasses through a venturi scrubber before entering a quench system. Theraw product stream can be cooled before it passes into the venturiscrubber.

The CFP product stream may comprise: on a water-free and solids-freebasis, the product stream of a catalytic pyrolysis process that issubjected to the inventive method comprises: 20 to 60%, or 25 to 55% or30 to 50%, or at least 20%, or at least 25%, or at least 30% COcalculated on a mass % basis; or 10 to 50%, or 15 to 40%, or 20 to 35%,or at least 5%, or at least 10%, or at least 15%, or at least 20% CO₂calculated on a mass % basis; or 0.1 to 2.0, or 0.2 to 1.5, or 0.3 to0.75%, or at least 0.1%, or at least 0.2%, or at least 0.3%, or lessthan 10%, or less than 5%, or less than 1% H₂ calculated on a mass %basis; or 2 to 40, or 3 to 35 or 4 to 30%, or less than 40%, or lessthan 35%, or less than 30%, or less than 20% BTX calculated on a mass %basis; or 0.1 to 10, or 0.2 to 5, or 0.3 to 3%, or less than 5%, or lessthan 3%, or less than 2% oxygenates calculated on a mass % basis. Insome embodiments, in the product stream, xylenes comprise at least 50%,or at least 60%, or at least 70%, or from 50 to 95%, or from 60 to 90%,or from 70 to 85% by weight.

The product stream from the catalytic pyrolysis process prior to anyquenching or separation is termed the raw product and, in someembodiments, the recovery of benzene is greater than 75, or greater than85, or greater than 90, or greater than 95, or greater than 97%, or from75 to 99%, or from 90 to 98%, or from 95 to 97.5% of the benzene in theraw product, or the recovery of toluene is greater than 75, or greaterthan 85, or greater than 90, or greater than 95, or greater than 97%, orfrom 75 to 99%, or from 90 to 98.5%, or from 95 to 98% of the toluene inthe raw product, or the recovery of xylenes is greater than 75, orgreater than 85, or greater than 90, or greater than 92%, or from 75 to99%, or from 85 to 98%, or from 90 to 93% of the xylenes in the rawproduct, or the recovery of the sum of ethylbenzene, styrene, and cumeneis greater than 70, or greater than 80, or greater than 85, or greaterthan 89%, or from 70 to 99%, or from 85 to 95%, or from 88 to 90% of theethylbenzene, styrene, and cumene in the raw product, or the recovery ofnaphthalene is greater than 85, or greater than 90, or greater than 95,or greater than 97, or greater than 99%, or from 85 to 100%, or from 95to 99.9%, or from 99 to 99.8% of the naphthalene in the raw product, orany combination of these.

In some embodiments, the pH of the water used for the quench iscontrolled by the addition or removal of acids, bases, or buffersolutions. The aqueous stream may be fed to a stripper column to recoverdissolved hydrocarbon materials.

In some embodiments, the water used for quench contains a corrosioninhibitor. In some preferred embodiments, the corrosion inhibitor ischosen from among amines, alkanolamines, imidazoline, phosphatedethoxylated alcohols/benzotriazole derivatives, or any other materialthat reduces metal corrosion. In some embodiments, a surfactant emulsionbreaking compound is added to the first liquid products. In somepreferred embodiments, the surfactant emulsion breaking compound ischosen from among amines, amyl-, butyl-, or nonyl resins, esters,polyols, polyol esters, sulfonates, or other material that breaksaqueous and organic emulsions, or some combination thereof.

In another aspect, the invention provides a method for producingaromatic chemicals from the product stream of a catalytic pyrolysisprocess, comprising: quenching the product stream with an organic quenchfluid to form a quenched product stream, separating a first vapor phaseand a first liquid phase from the quenched product stream, quenching thefirst vapor phase with water to form a quenched first vapor phase;separating a second vapor phase and a second liquid phase from thequenched first vapor phase, and recovering aromatics from the secondvapor phase. In some preferred embodiments, the organic quench fluidcomprises materials chosen from among diesel fuel, pyrolysis oil, pygas,jet fuel, heavy cycle oils, heavy coker gas oils, heavy visbreakingdistillates, heavy thermal cracking distillates clarified catalyticcracking decant oils, vacuum gas oil, intermediate and heavy vacuumdistillates, naphthenic oils, heavy hydrocracker distillates, heavydistillates from hydroprocessing, naphtha, C9+ organics, oxygenates,product streams from the CFP process, benzene, toluene, xylenes, ethylbenzene, styrene, cumene, propyl benzene, indane, indene, 2-ethyltoluene, 3-ethyl toluene, 4-ethyl toluene, trimethyl benzene (e.g.,1,3,5-trimethyl benzene, 1,2,4-trimethyl benzene, 1,2,3-trimethylbenzene, etc.), ethylbenzene, styrene, cumene, methylbenzene,propylbenzene, naphthalene, methyl-naphthalene (e.g., 1-methylnaphthalene), anthracene, 9.10-dimethylanthracene, pyrene, phenanthrene,dimethyl-naphthalene (e.g., 1,5-dimethylnaphthalene,1,6-dimethylnaphthalene, 2,5-dimethylnaphthalene, etc.),ethyl-naphthalene, hydrindene, methyl-hydrindene, dimethyl-hydrindene,phenol, o-cresol, m-cresol, p-cresol, catechol, resorcinol,hydroquinone, 1-naphthol, 2-naphthol, benzofuran, or combinationsthereof. Preferably, the organic quench fluid comprises at least 10, orat least 25, or at least 50, or at least 75, or at least 90% by weightof materials produced from biomass.

The invention also includes product stream such as can be produced bythe inventive methods where the carbon in the product stream is derivedfrom biomass. Thus, for example, the invention includes a product streamwherein the sum of benzene plus toluene comprises at least 80%, at least85%, at least 90%, at least 92%, or from 80 to 99%, or from 85 to 97%,or from 90 to 95% by weight; or a product stream as wherein xylenescomprise at least 50%, or at least 60%, or at least 70%, or from 50 to95%, or from 60 to 90%, or from 70 to 85% by weight.

In some aspects, the invention provides methods for producing aromaticchemicals from a catalytic pyrolysis product stream by recovering andseparating at least a portion of the products into benzene-rich,toluene-rich, and xylenes-rich fractions, and returning a portion of theheavier or lighter hydrocarbon product to the product recovery system.

In preferred embodiments of the inventive method, apparatus, and/orsystem, the pyrolysis reactor contains a solid catalyst. The solidcatalyst preferably comprises a zeolite, more preferably a zeolite and ametal and/or a metal oxide. The solid catalyst in the CFP reactor maycomprise elements such as, for example, silicon, aluminum, titanium,vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc,gallium, platinum, palladium, silver, tin, phosphorus, sodium,potassium, magnesium, calcium, tungsten, zirconium, cerium, lanthanum,and combinations thereof. Additional catalyst materials or inert solidsmay also be present. In some preferred embodiments, the CFP reaction iscatalyzed by a zeolite. In some embodiments, the zeolite comprises poresizes in the range of 5.0 to 6.5 angstroms. In some preferredembodiments, the catalyst comprises ZSM5. In some preferred embodiments,the mass ratio of catalyst fed to the reactor to hydrocarbonaceousmaterial fed to the reactor is between 0.1 and 40. In some preferredembodiments, the CFP reactor is a fluidized bed, circulating bed, orriser reactor. In some preferred embodiments, the temperature within thereactor is between 300 and 1000° C. In any of the inventive aspects, thepyrolysis step(s), (and/or any selected process step) may preferably beconducted at a pressure (absolute) of 30 atm or less, more preferably ofless than 10 atm, in some embodiments less than 1 atm; and in someembodiments in the range of 0.1 to 10 atm.

The hydrocarbonaceous material fed to the reactor may comprise a biomassmaterial; or plastic waste, recycled plastics, agricultural andmunicipal solid waste, food waste, animal waste, carbohydrates, orlignocellulosic materials; or the hydrocarbonaceous material cancomprise xylitol, glucose, cellobiose, cellulose, hemi-cellulose, orlignin; or the hydrocarbonaceous material may comprise sugar canebagasse, glucose, wood, or corn stover, or any of these materials in anycombination. The hydrocarbonaceous material that is fed to the reactortypically comprises a solid hydrocarbonaceous material, often in thepresence of a gas. In some preferred embodiments, the hydrocarbonaceousmaterial is at least 90 mass % solids. In some lesser preferredembodiments the hydrocarbonaceous material could be only in the gasand/or a liquid or slurry phase. In some embodiments, a recycle stream,preferably an aqueous recycle stream, can be contacted with thehydrocarbonaceous material before the hydrocarbonaceous material is fedto the reactor.

The invention includes methods, apparatus, and systems (which compriseapparatus plus process streams (that is, fluid compositions) and mayfurther be characterized by conditions such as temperature or pressure).Thus, any of the descriptions herein apply to the inventive methods,apparatus and systems.

Advantages of various aspects of the invention may include: increasedyield, improved energy efficiency, isolation of especially desirableproducts and product mixtures, and reduced pollution.

GLOSSARY

Aromatics—As used herein, the terms “aromatics” or “aromatic compound”are used to refer to a hydrocarbon compound or compounds comprising oneor more aromatic groups such as, for example, single aromatic ringsystems (e.g., benzyl, phenyl, etc.) and fused polycyclic aromatic ringsystems (e.g. naphthyl, 1,2,3,4-tetrahydronaphthyl, etc.). Examples ofaromatic compounds include, but are not limited to, benzene, toluene,indane, indene, 2-ethyl toluene, 3-ethyl toluene, 4-ethyl toluene,trimethyl benzene (e.g., 1,3,5-trimethyl benzene, 1,2,4-trimethylbenzene, 1,2,3-trimethyl benzene, etc.), ethylbenzene, styrene, cumene,methylbenzene, propylbenzene, xylenes (e.g., p-xylene, m-xylene,o-xylene), naphthalene, methyl-naphthalene (e.g., 1-methyl naphthalene),anthracene, 9.10-dimethylanthracene, pyrene, phenanthrene,dimethyl-naphthalene (e.g., 1,5-dimethylnaphthalene,1,6-dimethylnaphthalene, 2,5-dimethylnaphthalene, etc.),ethyl-naphthalene, hydrindene, methyl-hydrindene, anddymethyl-hydrindene. Single-ring and/or higher ring aromatics may alsobe produced in some embodiments. Aromatics also include single andmultiple ring compounds that contain heteroatom substituents, i.e.,phenol, cresol, benzofuran, aniline, indole, etc.

Biomass—As used herein, the term “biomass” is given its conventionalmeaning in the art and is used to refer to any organic source of energyor chemicals that is renewable. Its major components can be: (1) trees(wood) and all other vegetation; (2) agricultural products and wastes(corn, fruit, garbage ensilage, etc.); (3) algae and other marineplants; (4) metabolic wastes (manure, sewage), and (5) cellulosic urbanwaste. Examples of biomass materials are described, for example, inHuber, G. W. et al, “Synthesis of Transportation Fuels from Biomass:Chemistry, Catalysts, and Engineering,” Chem. Rev. 106, (2006), pp.4044-4098.

Biomass is conventionally defined as the living and recently deadbiological material that can be converted for use as fuel or forindustrial production. The criterion for biomass is that the materialshould be recently participating in the carbon cycle so that the releaseof carbon in the combustion process results in no net increase averagedover a reasonably short period of time (for this reason, fossil fuelssuch as peat, lignite and coal are not considered biomass by thisdefinition as they contain carbon that has not participated in thecarbon cycle for a long time so that their combustion results in a netincrease in atmospheric carbon dioxide). Most commonly, biomass refersto plant matter grown for use as biofuel, but it also includes plant oranimal matter used for production of fibers, chemicals or heat. Biomassmay also include biodegradable wastes or byproducts that can be burnt asfuel or converted to chemicals, including municipal wastes, green waste(the biodegradable waste comprised of garden or park waste, such asgrass or flower cuttings and hedge trimmings), byproducts of farmingincluding animal manures, food processing wastes, sewage sludge, blackliquor from wood pulp or algae. Biomass excludes organic material whichhas been transformed by geological processes into substances such ascoal, oil shale or petroleum. Biomass is widely and typically grown fromplants, including miscanthus, spurge, sunflower, switchgrass, hemp, corn(maize), poplar, willow, sugarcane, and oil palm (palm oil) with theroots, stems, leaves, seed husks and fruits all being potentiallyuseful. Processing of the raw material for introduction to theprocessing unit may vary according to the needs of the unit and the formof the biomass.

Catalysts—Catalyst components useful in the context of this inventioncan be selected from any catalyst known in the art, or as would beunderstood by those skilled in the art. Catalysts promote and/or effectreactions. Thus, as used herein, catalysts lower the activation energy(increase the rate) of a chemical process, and/or improve thedistribution of products or intermediates in a chemical reaction (forexample, a shape selective catalyst). Examples of reactions that can becatalyzed include: dehydration, dehydrogenation, isomerization, hydrogentransfer, aromatization, decarbonylation, decarboxylation, aldolcondensation, molecular cracking and decomposition, and combinationsthereof. Catalyst components can be considered acidic, neutral or basic,as would be understood by those skilled in the art.

For catalytic fast pyrolysis, particularly advantageous catalystsinclude those containing internal porosity selected according to poresize (e.g., mesoporous and pore sizes typically associated withzeolites), e.g., average pore sizes of less than about 100 Angstroms(Å), less than about 50 Å, less than about 20 Å, less than about 10 Å,less than about 5 Å, or smaller. In some embodiments, catalysts withaverage pore sizes of from about 5 Å to about 100 Å may be used. In someembodiments, catalysts with average pore sizes of between about 5.5 Åand about 6.5 Å, or between about 5.9 Å and about 6.3 Å may be used. Insome cases, catalysts with average pore sizes of between about 7Angstroms and about 8 Å, or between about 7.2 Å and about 7.8 Å may beused.

In some preferred embodiments of CFP, the catalyst may be selected fromnaturally occurring zeolites, synthetic zeolites and combinationsthereof. In certain embodiments, the catalyst may be a ZSM-5 zeolitecatalyst, as would be understood by those skilled in the art.Optionally, such a catalyst can comprise acidic sites. Other types ofzeolite catalysts include: ferrierite, zeolite Y, zeolite beta,mordenite, MCM-22, ZSM-23, ZSM-57, SUZ-4, EU-1, ZSM-11, SAPO-31, SSZ-23,among others. In other embodiments, non-zeolite catalysts may be used;for example, WOx/ZrO2, aluminum phosphates, etc. In some embodiments,the catalyst may comprise a metal and/or a metal oxide. Suitable metalsand/or oxides include, for example, nickel, palladium, platinum,titanium, vanadium, chromium, manganese, iron, cobalt, zinc, copper,gallium, and/or any of their oxides, among others. In some casespromoter elements chosen from among the rare earth elements, i.e.,elements 57-71, cerium, zirconium or their oxides for combinations ofthese may be included to modify activity or structure of the catalyst.In addition, in some cases, properties of the catalysts (e.g., porestructure, type and/or number of acid sites, etc.) may be chosen toselectively produce a desired product.

Olefins—As used herein, the terms “olefin” or “olefin compound” (a.k.a.“alkenes”) are given their ordinary meaning in the art, and are used torefer to any unsaturated hydrocarbon containing one or more pairs ofcarbon atoms linked by a double bond. Olefins include both cyclic andacyclic (aliphatic) olefins, in which the double bond is located betweencarbon atoms forming part of a cyclic (closed-ring) or of an open-chaingrouping, respectively. In addition, olefins may include any suitablenumber of double bonds (e.g., monoolefins, diolefins, triolefins, etc.).Examples of olefin compounds include, but are not limited to, ethene,propene, allene (propadiene), 1-butene, 2-butene, isobutene (2 methylpropene), butadiene, and isoprene, among others. Examples of cyclicolefins include cyclopentene, cyclohexene, cycloheptene, among others.Aromatic compounds such as toluene are not considered olefins; however,olefins that include aromatic moieties are considered olefins, forexample, benzyl acrylate or styrene.

Oxygenates—Oxygenates include any organic compound that contains atleast one atom of oxygen in its structure such as alcohols (methanol,ethanol, etc.), acids (e.g. acetic acid, propionic acid, etc.),aldehydes (eg formaldehyde, acetaldehyde, etc), esters (eg methylacetate, ethyl acetate, etc.), ethers (eg dimethyl ether, diethyl ether,etc.), aromatics with oxygen containing substituents (eg phenol, cresol,benzoic acid etc.), cyclic ethers, acids, aldehydes, and esters (e.g.furan, furfural, etc.), and the like.

Pyrolysis—As used herein, the terms “pyrolysis” and “pyrolyzing” aregiven their conventional meaning in the art and are used to refer to thetransformation of a compound, e.g., a solid hydrocarbonaceous material,into one or more other substances, e.g., volatile organic compounds,gases and coke, by heat, preferably without the addition of, or in theabsence of, O₂. Preferably, the volume fraction of O₂ present in apyrolysis reaction chamber is 0.5% or less. Pyrolysis may take placewith or without the use of a catalyst. “Catalytic pyrolysis” refers topyrolysis performed in the presence of a catalyst, and may involve stepsas described in more detail below. Example of catalytic pyrolysisprocesses are outlined, for example, in Huber, G. W. et al, “Synthesisof Transportation Fuels from Biomass: Chemistry, Catalysts, andEngineering,” Chem. Rev. 106, (2006), pp. 4044-4098.

Recovery—The recovery of a component is the fraction (or percent) ofthat component that is present in the recovered product stream(s)compared to the amount of that component that is present in the reactoreffluent stream. For example if 10 grams of product A is present in theraw effluent and 8.5 grams of product A is present in the recoveredproduct stream(s), then the recovery of A is 8.5/10 or 0.85 (85%).

CFP Reaction Technology

Examples of apparatus and process conditions suitable for CFP aredescribed in U.S. Pat. 8,277,643 of Huber et al. and in the US PatentApplication 2013/0060070A1 of Huber et al. that are incorporated hereinby reference. Conditions for CFP of biomass may include one or anycombination of the following features (which are not intended to limitthe broader aspects of the invention): a zeolite catalyst, a ZSM-5catalyst; a zeolite catalyst comprising one or more of the followingmetals: titanium, vanadium, chromium, manganese, iron, cobalt, nickel,copper, zinc, gallium, platinum, palladium, silver, phosphorus, sodium,potassium, magnesium, calcium, tungsten, zirconium, cerium, lanthanum,and combinations thereof; a fluidized bed, circulating bed, or riserreactor; an operating temperature in the range of 300° to 1000° C.;and/or a solid catalyst-to-biomass mass feed ratio of between 0.1 and40.

CFP Products—Components identified in the raw product stream include1-methyl-2-cyclopropen-1-yl-benzene, 1-methylethyl-benzene,alpha-methylstyrene, 1-methylpropyl-benzene, 1-(2-furanyl)-ethanone,1-(4-hydroxy-3,5-dimethoxyphenyl)-ethanone, 1,1-dimethyl-1h-indene,1,1-dimethyl-cyclopropane, 1,2,3-trimethyl-benzene,1,2,3-trimethylindene, 1,2-butadiene, 1,2-dihydro-naphthalene,1,3,5-hexatriene, 1,3-bis(methylene)-cyclopentane, 1,3-cyclopentadiene,1,3-dimethyl-1h-indene, 1,3-pentadiene, 1,4,6-trimethyl-naphthalene,1,4-dimethyl-naphthalene, 1,4-pentadiene,1,5-dihydroxy-1,2,3,4-tetrahydronaphthalene, 1,5-heptadien-3-yne,1,5-hexadiyne, 1,6,7-trimethyl-naphthalene, 1-buten-3-yne,1-ethenyl-2-methyl-benzene, 1-ethenyl-3-methylene-cyclopentene,1-ethyl-2-methyl-benzene, 1-ethyl-4-methyl-benzene,1-ethyl-cyclopentene, 1-ethyl-naphthalene, 1h-indenol,1-methyl-1,3-cyclopentadiene, 1-methyl-2-cyclopropen-1-yl-benzene,1-methyl-9h-fluorene, 1-methyl-bicyclo[2.2.1]hept-2-ene,1-methyl-cyclohexene, 1-methyl-cyclopentene, 1-methyl-indan,1-methyl-naphthalene, 1-naphthalenol, 1-propenyl-benzene,2-(1-methylethoxy)-ethanol, 2,3,6-trimethyl-phenol,2,3-dihydro-4,7-dimethyl-1h-indene, 2,3-dihydro-benzofuran,2,3-dimethyl-2-cyclopenten-1-one, 2,3-dimethyl-naphthalene,2,5-dimethyl-furan, 2,5-dimethyl-phenol, 2,6-dimethyl-naphthalene,2,6-dimethyl-phenol, 2-acetyl-5-norbornene, 2-butanone,2-cyclopenten-1-one, 2-ethyl-4-methyl-phenol, 2-ethyl-furan,2-ethyl-naphthalene, 2-ethyl-phenol, 2-hydroxyfluorene,2-hydroxy-propanenitrile, 2-methyl-1,1′-biphenyl,2-methyl-1,3-pentadiene, 2-methyl-1-butene, 2-methyl-1-naphthalenol,2-methyl-1-pentene, 2-methyl-6-(2-propenyl)-phenol,2-methyl-9h-fluorene, 2-methyl-benzofuran,2-methyl-bicyclo[3.2.0]hept-2-ene, 2-methyl-bicyclo[3.2.0]hept-2-ene,2-methyl-furan, 2-methyl-phenol (2-cresol), 2-methyl-propanal,2-naphthalenol, 2-phenanthrenol, 2-propenal, 2-vinylfuran,3,4-dimethylcyclopentene, 3,4-dimethyl-phenol, 3,5-dimethylcyclopentene,3-methyl-1,1′-biphenyl, 3-methyl-1,2-benzenediol,3-methyl-2-cyclopenten-1-one, 3-methyl-2-pentene,3-methyl-bicyclo[3.3.0]oct-2-en-8-one, 3-methyl-cyclohexene,3-methyl-cyclopentene, 3-methyl-furan, 3-methyl-phenanthrene,3-methyl-phenol (3-cresol), 3-phenyl-2-propenal4-cyclopentene-1,3-dione, 4-ethylcatechol,4-hydroxy-3,5-dimethoxy-benzaldehyde, 4-hydroxy-3-methylbenzaldehyde,4-methyl-1,2-benzenediol, 4-methyl-1,3-pentadiene,4-methyl-dibenzofuran, 4-phenylbut-3-ene-1-yne,5′-methyl-spiro[bicyclo[2.2.1]hept-5-ene-2,4′-[1,2]dioxolan]-3′-one,5-norbornane-2-carboxaldehyde, 7-methyl-benzofuran, 9h-fluoren-9-ol,9-methyl-anthracene, acetaldehyde, acetic acid, acetone, acetone,allene, alpha-methylstyrene, anthracene, benzene, benzofuran, bibenzyl,bicyclo[3.2.0]hepta-2,6-diene, biphenyl,bis-1,1′-(1-ethenyl-1,3-propanediyl)benzene, butanal, carbon dioxide,carbon monoxide, catechol, cis and trans-2-pentene, cis-2-butene,coumarin, cyclobutane, cyclohexene, cyclopentane, cyclopentene,dibenzofuran, ethane, ethyl-2-benzofuran, ethylbenzene, ethylene,fluorene, furan, hydrogen, hydroquinone, indane, isopropyl alcohol,isopropyl-benzene (cumene), mesitylene, methacrolein, methane, methylvinyl ketone, methyl-cyclopentane, m-xylene, naphthalene,o-hydroxybiphenyl, o-xylene, phenol, p-hydroxybiphenyl, propanal,propene, propyl-benzene, p-xylene, quinoline, styrene, toluene,trans-2-butene, and water.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a process for converting biomass into aromatics.

FIG. 2 presents a schematic of a recovery and quench system for BTXrecovery from CFP of biomass

FIG. 3 presents a schematic of a BTX separation process

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 shows an exemplary process for converting biomass to aromatics(BTX) and other components (C9+). Biomass is introduced and prepared instage 10 by chipping, drying, grinding, or other processes, or somecombination of these. The prepared biomass is introduced along with arecycle gas or transport fluid into the CFP reactor. The CFP reactor isa fluidized bed catalytic reactor that is fluidized by a portion ofrecycle gas or other fluid. The products from the CFP reactor areseparated from some of the catalyst, minerals, or char that is carriedalong with the fluid stream in one or more cyclones. The catalyst fromthe cyclones and other catalyst removed from the reactor is regeneratedin a catalyst regeneration system 50 in which the coke and char arecombusted and the catalyst is cooled and returned to the reactor, orsimply returned to the reactor. The raw fluid product is sent to aproduct recovery system 30 where the liquid products benzene, toluene,xylenes, naphthalenes, oxygenates, and other useful products arequenched, recovered, and separated from the non-condensable gases, i.e.,CO, CO₂, CH₄, H₂, and light olefins and paraffins, and the water, char,coke, ash, and catalyst fines. A portion of the gases is purged, and aportion is optionally recycled for use in the CFP reactor. The crudemixture of BTX and other products is separated into various fractions inseparation step 40 producing a water stream that can be recycled or sentto a water treatment system or otherwise utilized, a heavy fraction thatcontains C9+, oxygenates, and other materials, and various fractions ofbenzene, toluene, and xylenes.

FIG. 2 presents a schematic of a quench and recovery system forproducing benzene, toluene, xylenes, oxygenates, and C9+ products from abiomass CFP process. In FIG. 2 the CFP reactor 100 produces a productstream at a high temperature that is cooled in heat exchanger 110 andsent to a quench system 120. The raw product effluent is passed throughat least one cyclone (see FIG. 1) that removes much of the solids in themixture. In one option a venturi scrubber is placed upstream of thequench system to remove additional particulates including char, coke,catalyst, and ash. The quench system 120 contacts a stream of water withthe gaseous product stream. This quenching water may comprise reactionproduct water made by pyrolysis and catalytic conversion of biomass.Optionally the quench water may comprise clean make-up water.Optionally, the quench water may contain corrosion inhibitors such asamines, alkanolamines, imidazoline, phosphated ethoxylatedalcohols/benzotriazole derivatives, or any other material that reducesmetal corrosion, The pH of the quenching water may be controlled by theaddition or removal of acids, bases, or buffer solutions to achieve adesired pH. Optionally, an organic product stream from the process maybe recycled to the quench unit to improve process operability. Theorganic product stream recycled to the quench unit can be one thatcomprises BTX, benzene and toluene, or a mixed xylenes stream fromwithin the process, such as those produced in the BTX separationdistillation column. The product streams from the quench system 120include: a condensed stream that comprises water and organics comprisingC9+0 aromatics, oxygenates, and other compounds, and solids, and agas/vapor product stream that comprises benzene, toluene, xylenes, CO,CO₂, CH₄, N₂, H₂, C2-C4 olefins and paraffins, and other compounds. Thegas/vapor product stream from quench system 120 is passed to acompressor 130 and a heat exchanger 131. Heat exchanger 131 cools thestream and condenses recoverable hydrocarbon products. This cooling andcondensing can optionally be performed by air cooled, water cooled, orchilled water cooled exchangers, or some combination of these. Thecompressed and cooled product stream is passed to a 3-phase separator140. The gaseous stream from 140 (Stream 14) is sent to absorber 150 inwhich the gases are scrubbed with a mixed-xylenes containing absorptionliquid stream obtained from the BTX separation or other liquid streamrecovered from the process, to recover BTX from the gases. The liquidproduct from 150 (Stream 15) is optionally combined with the liquidphase from 140 (Stream 20) and the combined product stream may be sentto a BTX separation unit 200 described in more detail in FIG. 3.Alternatively, liquid streams from 140 and 150 may be separately sent tothe distillation unit 210 in FIG. 3. The gas stream from absorber 150that comprises the lighter components and fixed gases (CO, CO₂, H₂, CH₄,N₂, C2-C4 olefins and alkanes, etc.) is in part sent back to the reactorto fluidize the catalyst and provide a source of reactive olefins whichcan react in the presence of biomass to produce additional aromaticproduct. Any gas in excess of reactor fluidizing and olefin reactionrequirements can be used for other processing needs, combusted, orpurged. The aqueous stream from phase separator 140 is sent to the waterpurge stream. The water and high boiling point components from quenchsystem 120 are sent to an aqueous/organics separator 170. Optionally asurfactant emulsion breaking compound such as an amine, amyl-, butyl-,or nonyl resin, ester, polyol, polyol ester, sulfonate, or othermaterial as commercially available from Weatherford or Nalco may beadded to the quench system liquid products. The organics phase from 170that comprises C9+ aromatics (Stream 19) is pumped by pump 172 and sentto storage or a portion may be used in the process. The water phase(Stream 17) from 170 is pumped in pump 171 and a portion of the streamis passed through optional air cooler 180, heat exchanger 181, andrecycled to the quench system. Optionally, a portion of aqueous stream17 can be fed to a stripper column (not shown) to recover dissolvedhydrocarbon materials which can be recycled back to the absorber tower150 or recovered. Filters (not shown) can be placed after separator 170or at other locations in the flow scheme to remove particulates, char,ash, and catalyst fines not collected in the C9+ separator from theorganic and water streams. The remainder of the water is purged from thesystem and sent to water treatment. Venturi scrubbers are known in theart, and typically a venturi scrubber consists of three sections: aconverging section, a throat section, and a diverging section. The inletgas stream enters the converging section and, as the area decreases, gasvelocity increases. Liquid is introduced either at the throat or at theentrance to the converging section. The inlet gas moves at extremelyhigh velocities in the small throat section producing turbulence, whichcauses break-up of the liquid into an enormous number of small drops.The small drops intercept and coalesce with the small, entrainedparticulates, tar, char, ash, coke and catalyst fines in the gas stream.The inlet streams then exit through the diverging section, where it isforced to slow down. The liquid and particulates are collected in acollection vessel downstream of the venturi and the vapors exit from thetop of the collection vessel. As one non-limiting example, venturisystems are described in U.S. Pat. No. 5,279,646, which is incorporatedherein by reference.

Stream 20 from phase separator 140 comprises benzene, toluene, andxylenes (collectively BTX). The composition of the BTX stream 20comprises at least 50%, or at least 65%, or at least 75%, or at least85%, or from 65 to 99%, or from 75 to 95%, or from 80 to 92%, or from 85to 90% by mass BTX. The water content of the BTX stream 20 is less than10%, or less than 5%, or less than 1%, or less than 0.5%, or less than0.25%, or from 0.01 to 0.5%, or from 0.05 to 0.25%, or from 0.10 to0.20% by mass. The oxygenates in the BTX stream 20 comprises less than5%, or less than 2%, or less than 1%, or less than 0.25%, or from 0.01to 5%, or from 0.03 to 2%, or from 0.05 to 1% by mass.

Stream 19 from separation unit 170 comprises a C9+ aromatics-containingproduct stream. The product stream 19 comprises at least 80%, at least85%, at least 90%, or at least 95%, or from 60 to 99.8%, or from 80 to99.8%, or from 90 to 99.8% aromatics by mass. The product stream 19comprises at least 70%, or at least 75%, or at least 80%, or at least85%, or from 70 to 99%, or from 75 to 95%, or from 80 to 90% C9+aromatics by mass. The product stream 19 comprises at least 40%, or atleast 50%, or at least 60%, or from 40 to 90%, or from 50 to 80%, orfrom 60 to 70% naphthalene by mass. The product stream 19 comprises atleast 40%, or at least 50%, or at least 60%, or from 40 to 90%, or from50 to 80%, or from 60 to 70% polycyclic aromatics by mass. The productstream 19 comprises less than 25%, or less than 20%, or less than 15%,or less than 10%, or from 1 to 25%, or from 5 to 20% monocyclicaromatics by mass. The product stream 19 comprises less than 25%, orless than 15%, or less than 10%, or from 0.1 to 25%, or from 1 to 15%,or from 2 to 10% oxygenates by mass. The product stream 19 comprisesless than 5%, or less than 3%, or less than 1.5%, or less than 1%, orfrom 0.001 to 5%, or from 0.01 to 3%, or from 0.05 to 1.5%, or from 0.1to 1% water by mass.

Stream 17 from separator 170 comprises a water product or water recyclestream, or both. Stream 17 comprises at least 85%, or at least 90%, orat least 95% water by mass. Stream 17 comprises less than 10%, or lessthan 5%, or less than 3%, or less than 2%, or from 0.1 to 10%, or from0.5 to 5%, or from 1 to 3% aromatics by mass. Stream 17 comprises lessthan 10%, or less than 5%, or less than 2%, or less than 1%, or from0.05 to 10%, or from 0.1 to 5%, or from 0.5 to 3% oxygenates by weight.Stream 17 comprises less than 2%, or less than 1%, or less than 0.1%, orless than 0.05%, or from 0.0001 to 2%, for from 0.0005 to 1%, or from0.001 to 0.1% BTX by mass.

The pH of the water used for the quench unit 120 may be controlled bythe addition or removal of acids, bases, or buffer solutions to achievea desired pH. The pH can be at least 1.0, or at least 2.0, or at least3.0, or at least 4.0, or at least 5.0, or at least 6.0, or at least 7.0,or at least 8.0, or at least 9.0, or at least 10.0, or at least 11.0, orless than 2.0, or less than 3.0, or less than 4.0, or less than 5.0, orless than 6.0, or less than 7.0, or less than 8.0, or less than 9.0, orless than 10.0, or less than 11.0. The pH of the quench water can beadjusted and controlled by addition of acids, or bases, or buffersolutions as required to meet the desired pH. Acid materials derivedfrom the process can be used to control the pH of the quench water.

FIG. 3 summarizes the separation scheme for separating benzene andtoluene (BT) from xylenes (X). The mixed BTX stream from the recoverysystem in FIG. 3 is heated with hot mixed-xylenes product or otherwisein heat exchanger 202 and then fed to distillation column 210. Stream 15that comprises the liquid stream from absorber 150 in FIG. 2 is also fedto distillation column 210, optionally after being heated. In oneembodiment stream 15 and stream 20 from FIG. 2 are combined forintroduction to the distillation column. Distillation column 210 isheated by reboiling a take-off stream with high pressure steam althoughother methods such as reboiling with a natural gas fired furnace areenvisioned as being within the scope of this invention. A light fractionof product that comprises a BT mixture is passed to condenser 212 andthe condensed liquids are collected in collector 230. This lighterfraction can optionally be air cooled, water cooled, or chilled watercooled, or some combination of these. A fraction of the condensedliquids are returned to the distillation column 210 via pump 240 and theremainder of the BT stream is sent to storage for further purification.The overhead vapors from the BT condensation are combusted in a COfurnace boiler to generate steam, or optionally sent to a gas turbine togenerate electricity in a combined cycle scheme, or sent to a thermaloxidizer or flare, or can be employed in the CFP process, or can be sentto a downstream process for further recovery of products or usedelsewhere. The condensed aqueous phase that collects in collector 230 issent to water treatment. A portion of the xylenes rich fraction ispumped via pump 220 from distillation column 210 to heat the incomingcrude BTX mixture, cooled in heat exchanger 204 and sent to the absorber150 in FIG. 2. The remainder of the xylenes rich fraction is sent tostorage and further purification. The bottom ends from distillationcolumn 210 are heat exchanged to raise steam (not shown), optionallycooled, and pumped via pump 250 to storage or further upgraded.

Absorber 150 in FIG. 2 may be a conventional absorber system known tothose skilled in the art. The absorber can be a packed bed absorber. Apreferred absorber solvent is a mixed-xylenes stream. When amixed-xylenes stream is used as the absorber fluid the absorber isoperated at a relatively low operating temperature of from −20 to 50 C,or from −5 to 30 C, or most preferably from 5 C to 10 C. The absorber isoperated at elevated pressure from 100 kPa to 7000 kPa, or from 200 kPato 7000 kPa, or most preferably the pressure of this absorption step isless than 1500 kPa, or less than 1200 kPa, or less than 1000 kPa. Thefeed ratio of liquid mixed xylenes to vapors for absorber 150 can rangefrom 0.001 to 2, or from 0.002 to 1, or from 0.005 to 0.5, or morepreferably from 0.01 to 0.1, or less than 0.1, or less than 0.05, orless than 0.02 on a molar basis, ie moles of mixed xylenes divided bymoles of vapor. Distillation column 210 may be a conventionaldistillation column or a divided wall column as is known to thoseskilled in the art, which contains at least 5 or at least 10 or at least20 or at least 30, or at least 50 theoretical plates or stages ofdistillation.

The quench system described herein has a variety of advantages inrecovering products from a CFP process. The quench cools the productvapors and condenses reaction product water along with heavy aromatics,and oxygenates. The whole product inlet temp to the quench system canrange from 200 to 620 C, or from 400 to 550 C, or preferably from 425 to500 C The ratio of water to gas feed can range from 0.1:1 to 100:1 byweight, or from 0.5:1 to 20:1 by weight or from 1:1 to 10:1 by weight,or from 2:1 to 5:1 by weight. Quenching with water removes the greatmajority of the heavy C9+ hydrocarbons, oxygenates such as phenol andcresol, allowing further downstream vapor processing by cooling which isnot otherwise possible due to the high melting point of some componentsof the C9+ material, e.g., naphthalene, m.p. 80° C. In some embodimentsof this invention the temperature of the overhead vapor stream 12 fromthe quench system 120 in FIG. 2 is from 10° C. to 200° C., or from 20°C. to 150° C., or from 30° C. to 100° C., or from 40° C. to 80° C., orfrom 50° C. to 70° C. The overhead pressure of the vapor stream from thequench system can range from 100 kPa to 4000 kPa, or from 150 kPa to1500 kPa, or from 200 kPa to 1000 kPa, or from 300 kPa to 700 kPa. Theoverhead vapor from the quench contains most of the aromatics. Thisvapor can then be processed further to recover BTX and other aromaticcompounds.

The quench also functions as a water wash that removes particulatematerial such as char, coke, ash, tar and catalyst fines that carry overfrom the reactor cyclones. These particles may collect in the liquidphase and can be removed from the system by gravity separation,filtration or other downstream process steps known to those skilled inthe art. The collected solids can optionally be returned to the catalystregeneration step or can be collected for separation and recovery ofvaluable components. Removal of fine particulates in the water quenchsystem protects other downstream equipment from damage, particularly therecycle compressor. Another advantage is that the water needed for thequench can be generated in the process when it is operating at steadystate rendering the process independent of water sources other thanwater needed for startup.

Optionally a preliminary quench that uses an organic quench fluid isconducted upstream of the water quench. In the preliminary quench thequench fluid comprises an organic phase in which most of the materialhas a higher boiling point than the BTX materials, i.e. at least 140 C.The fraction of the organic quench fluid that boils at temperaturesabove 140 C is at least 50, or at least 60, or at least 70, or at least80, or at least 90, or at least 95, or at least 97, or at least 99% byweight of the organic quench fluid. The organic quench fluid comprisesfluids chosen from among naphtha, C9+ organics, oxygenates, productstreams from the CFP process, benzene, toluene, xylenes, ethyl benzene,styrene, cumene, propyl benzene, indane, indene, 2-ethyl toluene,3-ethyl toluene, 4-ethyl toluene, trimethyl benzene (e.g.,1,3,5-trimethyl benzene, 1,2,4-trimethyl benzene, 1,2,3-trimethylbenzene, etc.), ethylbenzene, styrene, cumene, methylbenzene,propylbenzene, naphthalene, methyl-naphthalene (e.g., 1-methylnaphthalene), anthracene, 9.10-dimethylanthracene, pyrene, phenanthrene,dimethyl-naphthalene (e.g., 1,5-dimethylnaphthalene,1,6-dimethylnaphthalene, 2,5-dimethylnaphthalene, etc.),ethyl-naphthalene, hydrindene, methyl-hydrindene, dimethyl-hydrindene,phenol, o-cresol, m-cresol, p-cresol, catechol, resorcinol,hydroquinone, 1-naphthol, 2-naphthol, and benzofuran or combinationsthereof. The organic quench fluid comprises at least 25, or at least 40,or at least 50, or at least 65 or at least 80% by weight aromaticcompounds. The organic quench fluid may comprise a portion of one ormore product streams of the CFP process, e.g. stream 25 of FIG. 3 orstream 19 of FIG. 2 or some combination of these. The organic quenchfluid may comprise less than 50, or less than 40, or less than 30, orless than 20 or less than 10, or less than 5, or less than 2% by weightwater. The organic quench fluid may be a two phase mixture of an organicphase and an aqueous phase, or an emulsion of organic and aqueousphases. The quench fluid may comprise diesel fuel, pyrolysis oil, pygas(pygas is a naphtha-range product with a high aromatics content producedin high temperature naphtha cracking during ethylene and propyleneproduction), jet fuel, heavy cycle oils, heavy coker gas oils, heavyvisbreaking distillates, heavy thermal cracking distillates clarifiedcatalytic cracking decant oils, vacuum gas oil, intermediate and heavyvacuum distillates, naphthenic oils, heavy hydrocracker distillates,heavy distillates from hydroprocessing, or the like, or combinationsthereof. In some embodiments the organic quench fluid comprises organicmaterials from a conventional petroleum refinery. Preferably the organicquench fluid comprises at least 10, or at least 25, or at least 50, orat least 75, or at least 90% by weight of materials produced frombiomass.

In some embodiments the stream produced in the optional organic quenchis passed directly into the water quench. In other embodiments theproduct stream is separated into a vapor and a liquid stream and onlythe vapor stream is passed into the water quench. In one embodiment theliquid stream produced in and separated from the organic quench ispassed into the recovery section as in stream 12 in FIG. 2. In anotherembodiment the liquid stream produced in and separated from the organicquench is passed into a 3-phase separator as in unit 140 in FIG. 2wherein vapor, organic liquid, and aqueous streams are separated. Insome embodiments at least a portion of the organic liquid phaseseparated in the 3-phase separator is recycled for use as a portion ofthe organic quench liquid. In some embodiments the vapor phase from the3-phase separator is passed to the xylene absorber, 140, in FIG. 2.

A preferred embodiment of the present invention employs a mixed-xylenesstream in the product recovery. Another preferred embodiment uses anabsorbent fluid (solvent) that is a stream already present in theprocess such as xylenes, naphthalenes, C9+ mixtures, or some combinationof these, thus requiring no new solvent to be introduced to the process.In another embodiment the compressed and cooled stream exiting heatexchanger 131 enters absorber 150 directly without the use of a separate3-phase separator 140. In this case absorber 150 functions to separatethe 3 phases as well as absorb aromatic compounds from the vapor intothe organic liquid phase. A stream from the BTX column such as themixed-xylene side-stream cut can serve the purpose of generating thesolvent, or it can be recovered from the C9+/water separator, andtherefore there is no need for a solvent extraction/recovery system. Useof a stream that is already present in the process and recovery schemeprovides significant economic advantages and renders the processindependent of solvent supply other than at start-up.

Optionally, a solvent other than the xylenes stream shown in FIGS. 2 and3 can be used to recover the BTX products from the quenched productvapors. Other potential solvents include mixtures of hydrocarboncompounds such as stream 19, 22, or 25, or fractions thereof, or anysolvent derived from the process that has a higher boiling point thanbenzene and toluene and dissolves the aromatics. In some embodiments,the product recovery solvent stream may comprise materials chosen fromamong benzene, toluene, xylenes, ethyl benzene, styrene, cumene, propylbenzene, indane, indene, 2-ethyl toluene, 3-ethyl toluene, 4-ethyltoluene, trimethyl benzene (e.g., 1,3,5-trimethyl benzene,1,2,4-trimethyl benzene, 1,2,3-trimethyl benzene, etc.), ethylbenzene,styrene, cumene, methylbenzene, propylbenzene, naphthalene,methyl-naphthalene (e.g., 1-methyl naphthalene), anthracene,9.10-dimethylanthracene, pyrene, phenanthrene, dimethyl-naphthalene(e.g., 1,5-dimethylnaphthalene, 1,6-dimethylnaphthalene,2,5-dimethylnaphthalene, etc.), ethyl-naphthalene, hydrindene,methyl-hydrindene, dimethyl-hydrindene, phenol, o-cresol, m-cresol,p-cresol, catechol, resorcinol, hydroquinone, 1-naphthol, 2-naphthol,and benzofuran, or combinations thereof. In some embodiments, thecontacting solvent may comprise paraffins, aromatics, cycloparaffins,diesel fuel, jet fuel, or combinations of these.

The CFP process may be conducted at a temperature of 400° C. or more,and the product stream from 100 in FIG. 1 is typically at a temperatureof 300-620° C., or 400-575° C., or 500-550° C., and a pressure of 100kPa to 4000 kPa, or 200 kPa to 1000 kPa, or 300 kPa to 700 kPa, or atleast 200 kPa, or at least 300 kPa or at least 400 kPa. (Pressures areexpressed as absolute pressures.) The raw product stream from 100comprises aromatics, olefins, oxygenates, paraffins, H₂, CH₄, CO, CO₂,water, char, ash, coke, catalyst fines, and a host of other compounds.On a water-free and solids-free basis the raw product stream cancomprise 20 to 60%, or 25 to 55% or 30 to 50%, or at least 20%, or atleast 25%, or at least 30% CO calculated on a mass % basis. On awater-free and solids-free basis the raw product stream can comprise 10to 50%, or 15 to 40%, or 20 to 35%, or at least 5%, or at least 10%, orat least 15%, or at least 20% CO₂ calculated on a mass % basis. On awater-free and solids-free basis the raw product stream can comprise 0.1to 2.0, or 0.2 to 1.5, or 0.3 to 0.75%, or at least 0.1%, or at least0.2%, or at least 0.3%, or less than 10%, or less than 5%, or less than1% H₂ calculated on a mass % basis. On a water-free and solids-freebasis the raw product stream can comprise 2 to 15, or 3 to 10, or 4 to8%, or less than 15%, or less than 10%, or less than 8% CH₄ calculatedon a mass % basis. On a water-free and solids-free basis the raw productstream can comprise 2 to 40, or 3 to 35 or 4 to 30%, or less than 40%,or less than 35%, or less than 30%, or less than 20% BTX calculated on amass % basis. On a water-free and solids-free basis the raw productstream can comprise 0.1 to 10%, or 0.2 to 5%, or 0.3 to 3%, or less than5%, or less than 3%, or less than 2% oxygenates calculated on a mass %basis. On a water-free and solids-free basis the raw product stream cancomprise 1 to 15%, or 2 to 10%, or 3 to 6% C2-C4, or at least 1%, or atleast 2%, or at least 3% olefins calculated on a mass % basis. On awater-free and solids-free basis the raw product stream can comprise avapor mixture where the sum of CO and CO₂ is from 30 to 90, or from 40to 85, or from 50 to 80%, calculated on a mass % basis.

The quench water enters the quench system 120 at a temperature from −5to 100° C., or 20 to 60° C., or 30 to 55° C., or 35 to 50° C. Heatexchanger 110 typically cools the raw product stream to a temperature of250 to 600° C., or 350 to 550° C., or 400 to 500° C. The quenched,compressed, cooled product stream from heat exchanger 131 in FIG. 1 canbe separated in phase separator 140 held at a temperature of −30 to 60°C., or −15 to 40° C., or −5 to 30° C., or 0 to 10° C., and pressure from100 to 8000 kPa, or to from 500 to 4000 kPa, or from 600 to 2000 kPa.The organic vapor phase from separator 140 is contacted with a xylenes(or other solvent) stream in absorber 150 at a temperature −30 to 60°C., or −15 to 40° C., or −5 to 30° C., or 0 to 10° C., and pressure from100 and 7000 kPa, or to from 300 to 4000 kPa, or from 400 to 1000 kPa.

The crude BTX stream is heated by heat exchange against a mixed xylenesstream in 202 in FIG. 3 where the BTX stream enters at a temperaturefrom −10 to 150° C., or 0 to 50° C., or 2 to 20° C. and the mixedxylenes stream enters at a temperature from 50 to 300° C., or 100 to225° C., or 150 to 200° C. to be passed to the distillation step 210.

The distillation of the BTX rich stream in 210 can be accomplished byconventional methods using conventional distillation equipment such astray, bubble cap, packed columns, divided wall columns or the like.Distillation may be carried out at subatmospheric pressures or atatmospheric pressures or at higher pressures. Ordinarily, thisdistillation will be carried out at pressures from 1 to 1,000 kPa, orfrom 10 to 500 kPa, with pressures from 100 to 400 kPa being preferred.

The benzene and toluene (collectively BT) rich stream 27 that is aproduct stream of the process. Stream 27 can comprise at least 80%, atleast 85%, at least 90%, at least 92%, or from 80 to 99%, or from 85 to97%, or from 90 to 95% BT by weight. Stream 27 can comprise at least25%, or at least 30%, or at least 35%, or from 25 to 70%, or from 30 to60%, or from 35 to 50% benzene by weight. Stream 27 can comprise atleast 30%, or at least 35%, or at least 40%, or from 30 to 80%, or from35 to 70%, or from 40 to 60% toluene by weight. Stream 27 comprises lessthan 2%, or less than 1%, or less than 0.5% oxygenates by weight, orless than 0.1% oxygenates.

The product stream 28 comprises a mixed xylenes product stream. Stream28 can comprise at least 50%, or at least 60%, or at least 70%, or from50 to 95%, or from 60 to 90%, or from 70 to 85% xylenes (p-, o-, andm-xylenes) by weight. Product stream 28 can comprise less than 25%, orless than 20%, or less than 15%, or less than 12%, or from 1 to 25%, orfrom 3 to 20%, or from 5 to 15% benzene plus toluene by weight. Productstream 28 can comprise less than 20%, or less than 15%, or less than10%, or from 0.1 to 20%, or from 1 to 15%, or from 5 to 10% naphthaleneby weight.

The overhead mixed BT stream is further separated downstream in anotherfractionation column (not shown), or the benzene and toluene can beseparated in this column if the configuration allows it, for example ifit is a divided wall column. The BTX separation column 210 functions asa xylene stripper as well as a fractionator. Mixed xylenes leave thebottom of the column for further separation into para-, meta-, andortho-xylene. Conventional processes for separating the isomers ofxylene are known to those skilled in the art. The processes of thepresent invention provide for efficient recovery of the variouscomponents of the raw CFP product stream. The recovery of benzene in theinventive process is greater than 75, or greater than 85, or greaterthan 90, or greater than 95, or greater than 97%, or from 75 to 99%, orfrom 90 to 98%, or from 95 to 97.5% of the benzene in the raw product.The recovery of toluene in the inventive process is greater than 75, orgreater than 85, or greater than 90, or greater than 95, or greater than97%, or from 75 to 99%, or from 90 to 98.5%, or from 95 to 98% of thetoluene in the raw product. The recovery of xylenes in the inventiveprocess is greater than 75, or greater than 85, or greater than 90, orgreater than 92%, or from 75 to 99%, or from 85 to 98%, or from 90 to93% of the xylenes in the raw product. The recovery of the sum ofethylbenzene, styrene, and cumene in the inventive process is greaterthan 70, or greater than 80, or greater than 85, or greater than 89%, orfrom 70 to 99%, or from 85 to 95%, or from 88 to 90% of theethylbenzene, styrene, and cumene in the raw product. The recovery ofnaphthalene in the inventive process is greater than 85, or greater than90, or greater than 95, or greater than 97, or greater than 99%, or from85 to 100%, or from 95 to 99.9%, or from 99 to 99.8% of the naphthalenein the raw product. The recovery of each of these products is calculatedas the sum of the materials recovered in streams 20, 25, and 27 in FIG.3.

Example 1

The recovery and separation of a typical raw process stream was modeledin an ASPEN™ model following the schemes of FIGS. 2 and 3. In the modelthe input rate was 211,652 kg/hr of raw product from a CFP process withsolids not included. The stream compositions, temperatures, andpressures were calculated as shown in Table 1 for the process depictedin FIG. 2. The stream compositions, temperatures, and pressures werecalculated as shown in Table 2 for the process depicted in FIG. 3 exceptheat exchanger 202 was omitted from the modeling.

The recovery of benzene is calculated to be 97.3% of the benzene in theraw product stream. The recovery of toluene is calculated to be 97.9% ofthe toluene in the raw product stream. The recovery of xylenes iscalculated to be 92.9% of the xylenes in the raw product stream. Therecovery of styrene, ethylbenzene, and cumene is 89.5%, the recovery ofnaphthalene is 99.8%, and the recovery of indene is 95.5% of each ofthese materials in the raw product. The recoveries of benzofuran,aniline, indole, indene, naphthalene, 2-methylnaphthalene, phenol, andm-cresol are 43.0%, 39.7%, 41.3%, 99.5%, 99.9%, 48.2%, 17.4%, 42.6%,respectively, of these materials in the raw product stream.

The results from the Example show that high recovery rates of benzene,toluene, xylenes, ethylbenzene, cumene, styrene, naphthalene, andoxygenates can be obtained by the process of the present invention thatalso removes and collects tar, solid ash, char, catalyst, and coke.

High recovery efficiencies for BTX from a complex raw product streamthat contains very low concentrations of benzene, toluene, and xylenesis a surprising aspect of this invention. Separation and recovery of theBTX components from the non-condensable gases, water, heavy products,oxygenates, nitrogenates, and olefins would normally be expected to beplagued by significant losses of the desired materials due to their lowconcentrations and high vapor pressures. The novel arrangement of unitoperations and process conditions facilitates the recovery of BTX withminimal losses.

The use of a venturi scrubber to simultaneously remove particulates andunwanted condensable components from the product stream of a biomasspyrolysis process provides superior results in the separation of BTX.Current practice in the bio-oil and aromatics production industry doesnot use a venturi for such a purpose. Common industrial use of venturiscrubbers is to remove particulates and toxic fumes from gas streams forpollution control. In those conventional applications, the gas stream tobe cleaned contains non-condensable vapors. The ability of a venturiscrubber to simultaneously remove particulates, tars and separate otherheavy hydrocarbons in a biomass to bio-oil or aromatics process is aunique and surprising aspect of the invention.

Operation of the scrubber within a narrow temperature range providesenhanced aromatic recovery and C9+ rejection. Recovery of low boilingcomponents from a biomass pyrolysis mixture such as the raw productstream of CFP is limited due to the high vapor pressure of thesematerials and their tendency to distribute into both vapor and liquidorganic phases. Operation of a quench or condensation tower with anoverhead exit temperature that is too high permits substantial portionsof higher boiling materials and water to be passed along with thedesired BTX products into the recovery train causing the recovery trainto be much larger and less efficient. Operation of a quench orcondensation tower with an overhead exit temperature that is too lowtraps a significant fraction of the desired products with the quenchliquid, thus removing them from the recovery train and reducing theirrecovery efficiency. It is surprising that the overhead temperature ofthe quench unit can be adjusted to increase the removal of the heaviercomponents without losing a significant fraction of the desired BTXproducts, and yet the process stream has a low content of water andheavy products.

It is surprising that the BTX vapors in the overhead vapor streamcomprising primarily CO, CO₂, and CH₄ from the organics/aqueous phaseseparator can be recovered using a stream of xylenes from the processand still achieve a high recovery of xylenes. Conventional processes usehigh boiling aromatic and other solvents in absorbers. In some preferredapplications of the present invention, the pressure of this absorptionstep is at 1500 kPa or below, or 1200 kPa or below, or 1000 kPa orbelow, in some embodiments, the pressure is only about 900 kPa (135psig, 9 bar), and, at any of these pressures, the gas stream from whichBTX are to be recovered contains at least 60% (CO+CO2), or at least 70%,or at least 80% and in some embodiments, 70 to 95%, or 80% to 90%(CO+CO2) in addition to H₂, C₁-C₄ hydrocarbons, benzene, toluene, andtraces of xylenes and water. Under these conditions, it is surprisingthat xylene would effectively recover BTX from the product stream. It issurprising that recycling BTX or some portion of BTX to the quench unitimproves operability of the unit without significant reduction of therecovery of BTX from the process.

1-19. (canceled)
 20. An organic liquid product stream comprising atleast 80% aromatics by mass, at least 40% polycyclic aromatics by mass,less than 25% monocyclic aromatics by mass, less than 25% oxygenates bymass, and less than 5% water by mass, produced from the method of claim13.
 21. An organic liquid product stream comprising from 60 to 99.8%aromatics by mass, from 40 to 90% polycyclic aromatics by mass, from 1to 25% of monocyclic aromatics by mass, from 0.1 to 25% oxygenates bymass, and from 0.001 to 5% water by mass. 22-43. (canceled)
 44. Aproduct stream wherein the sum of benzene plus toluene comprises atleast 80%, at least 85%, at least 90%, at least 92%, or from 80 to 99%,or from 85 to 97%, or from 90 to 95% by weight.
 45. A product streamwherein xylenes comprise at least 50%, or at least 60%, or at least 70%,or from 50 to 95%, or from 60 to 90%, or from 70 to 85% by weight.46-52. (canceled)
 53. A method for producing aromatic chemicals from theproduct stream of a catalytic pyrolysis process, comprising: quenchingthe product stream with an organic quench fluid to form a quenchedproduct stream, separating a first vapor phase and a first liquid phasefrom the quenched product stream, quenching the first vapor phase withwater to form a quenched first vapor phase; separating a second vaporphase and a second liquid phase from the quenched first vapor phase,recovering aromatics from the second vapor phase.
 54. The method ofclaim 53 wherein the organic quench fluid comprises materials chosenfrom among diesel fuel, pyrolysis oil, pygas, jet fuel, heavy cycleoils, heavy coker gas oils, heavy visbreaking distillates, heavy thermalcracking distillates clarified catalytic cracking decant oils, vacuumgas oil, intermediate and heavy vacuum distillates, naphthenic oils,heavy hydrocracker distillates, heavy distillates from hydroprocessing,naphtha, C9+ organics, oxygenates, product streams from the CFP process,benzene, toluene, xylenes, ethyl benzene, styrene, cumene, propylbenzene, indane, indene, 2-ethyl toluene, 3-ethyl toluene, 4-ethyltoluene, trimethyl benzene (e.g., 1,3,5-trimethyl benzene,1,2,4-trimethyl benzene, 1,2,3-trimethyl benzene, etc.), ethylbenzene,styrene, cumene, methylbenzene, propylbenzene, naphthalene,methyl-naphthalene (e.g., 1-methyl naphthalene), anthracene,9.10-dimethylanthracene, pyrene, phenanthrene, dimethyl-naphthalene(e.g., 1,5-dimethylnaphthalene, 1,6-dimethylnaphthalene,2,5-dimethylnaphthalene, etc.), ethyl-naphthalene, hydrindene,methyl-hydrindene, dimethyl-hydrindene, phenol, o-cresol, m-cresol,p-cresol, catechol, resorcinol, hydroquinone, 1-naphthol, 2-naphthol,benzofuran, or combinations thereof.
 55. The process of claim 53 whereinthe organic quench fluid comprises at least 10, or at least 25, or atleast 50, or at least 75, or at least 90% by weight of materialsproduced from biomass.
 56. (canceled)